The present invention relates to gas turbine engines and, more particularly, to an apparatus for supporting a relatively cool member such as a fuel manifold to a relatively hot member such as a combustor housing in a manner to accommodate differential thermal growth and retain dynamic stability.
Conventional gas turbine engines for aircraft propulsion are axial flow engines having a forward compressor section, a mid-engine, combustor section and an aft turbine section. Centrally located shafts extend through the engine coupling the turbine section to the combustor section. The rotation of the elements in the compressor and turbine sections combined with the combustion and gas flow through the engine results in some degree of vibration throughout the engine. Various auxiliary components are supported on housings or other structural members associated with the enumerated engine sections. The supports or mounts for these auxiliary components desirably accommodate the engine vibrations.
In some areas of the engine generally beginning with the combustor section and extending aft, there exists a significant temperature differential between the auxiliary components and the adjacent engine section. For example, the fuel lines or fuel manifold adjacent the combustor carry relatively cool fuel and are at a substantially lower temperature than the adjacent combustor section. The fuel manifold is supported on brackets extending from the combustor. The temperature differential between the combustor and the manifold results in a significant differential growth which places a stress on the fuel manifold. The combination of this stress along with the aforementioned vibration may result in the development of cracks in the manifold from both low and high cycle fatigue. Accordingly, it is desirable to provide a method for coupling elements of different temperatures in a manner to minimize low cycle fatigue.
This can be accomplished using split brackets with overlapping ends and spring loading to accommodate thermal expansion. However, it has been found that without additional structure, such spring loaded joints tend to bind and inhibit the function they are intended to perform. Accordingly, it is desirable to provide a coupling method which overcomes the binding characteristic of a simple spring loaded slide bracket.